package com.peng.stack;

import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.Stack;
import java.util.regex.Pattern;

public class ReversePolishMultiCalc {

  /**
   * 匹配 + - * / ( ) 运算符
   */
  static final String SYMBOL = "\\+|-|\\*|/|\\(|\\)";
  static final Pattern pattern = Pattern.compile("^[-\\+]?[.\\d]*$");

  static final String LEFT = "(";
  static final String RIGHT = ")";
  static final String ADD = "+";
  static final String MINUS = "-";
  static final String TIMES = "*";
  static final String DIVISION = "/";

  /**
   * 加減 + -
   */
  static final int LEVEL_01 = 1;
  /**
   * 乘除 * /
   */
  static final int LEVEL_02 = 2;

  /**
   * 括号
   */
  static final int LEVEL_HIGH = Integer.MAX_VALUE;


  static Stack<String> stack = new Stack<>();
  static List<String> data = Collections.synchronizedList(new ArrayList<String>());

  /**
   * 去除所有空白符
   */
  public static String replaceAllBlank(String s) {
    // \\s+ 匹配任何空白字符，包括空格、制表符、换页符等等, 等价于[ \f\n\r\t\v]
    return s.replaceAll("\\s+", "");
  }

  /**
   * 判断是不是数字 int double long float
   */
  public static boolean isNumber(String s) {

    return pattern.matcher(s).matches();
  }

  /**
   * 判断是不是运算符
   */
  public static boolean isSymbol(String s) {
    return s.matches(SYMBOL);
  }

  /**
   * 匹配运算等级
   */
  public static int calcLevel(String s) {
    if ("+".equals(s) || "-".equals(s)) {
      return LEVEL_01;
    } else if ("*".equals(s) || "/".equals(s)) {
      return LEVEL_02;
    }
    return LEVEL_HIGH;
  }

  /**
   * 匹配
   */
  public static List<String> doMatch(String s) throws Exception {
    if (s == null || "".equals(s.trim())) {
      throw new RuntimeException("data is empty");
    }
    if (!isNumber(s.charAt(0) + "")) {
      throw new RuntimeException("data illeagle,start not with a number");
    }

    s = replaceAllBlank(s);

    String each;
    int start = 0;

    for (int i = 0; i < s.length(); i++) {
      if (isSymbol(s.charAt(i) + "")) {
        each = s.charAt(i) + "";
        //栈为空，(操作符，或者 操作符优先级大于栈顶优先级 && 操作符优先级不是( )的优先级 及是 ) 不能直接入栈
        if (stack.isEmpty() || LEFT.equals(each)
            || ((calcLevel(each) > calcLevel(stack.peek())) && calcLevel(each) < LEVEL_HIGH)) {
          stack.push(each);
        } else if (!stack.isEmpty() && calcLevel(each) <= calcLevel(stack.peek())) {
          //栈非空，操作符优先级小于等于栈顶优先级时出栈入列，直到栈为空，或者遇到了(，最后操作符入栈
          while (!stack.isEmpty() && calcLevel(each) <= calcLevel(stack.peek())) {
            if (calcLevel(stack.peek()) == LEVEL_HIGH) {
              break;
            }
            data.add(stack.pop());
          }
          stack.push(each);
        } else if (RIGHT.equals(each)) {
          // ) 操作符，依次出栈入列直到空栈或者遇到了第一个)操作符，此时)出栈
          while (!stack.isEmpty() && LEVEL_HIGH >= calcLevel(stack.peek())) {
            if (LEVEL_HIGH == calcLevel(stack.peek())) {
              stack.pop();
              break;
            }
            data.add(stack.pop());
          }
        }
        start = i;    //前一个运算符的位置
      } else if (i == s.length() - 1 || isSymbol(s.charAt(i + 1) + "")) {
        each = start == 0 ? s.substring(start, i + 1) : s.substring(start + 1, i + 1);
        if (isNumber(each)) {
          data.add(each);
          continue;
        }
        throw new RuntimeException("data not match number");
      }
    }
    //如果栈里还有元素，此时元素需要依次出栈入列，可以想象栈里剩下栈顶为/，栈底为+，应该依次出栈入列，可以直接翻转整个stack 添加到队列
    Collections.reverse(stack);
    data.addAll(new ArrayList<>(stack));

    System.out.println(data);
    return data;
  }

  /**
   * 算出结果
   */
  public static Double doCalc(List<String> list) {
    Double d = 0d;
    if (list == null || list.isEmpty()) {
      return null;
    }
    if (list.size() == 1) {
      System.out.println(list);
      d = Double.valueOf(list.get(0));
      return d;
    }
    ArrayList<String> list1 = new ArrayList<>();
    for (int i = 0; i < list.size(); i++) {
      list1.add(list.get(i));
      if (isSymbol(list.get(i))) {
        Double d1 = doTheMath(list.get(i - 2), list.get(i - 1), list.get(i));
        list1.remove(i);
        list1.remove(i - 1);
        list1.set(i - 2, d1 + "");
        list1.addAll(list.subList(i + 1, list.size()));
        break;
      }
    }
    doCalc(list1);
    return d;
  }

  /**
   * 运算
   */
  public static Double doTheMath(String s1, String s2, String symbol) {
    Double result;
    switch (symbol) {
      case ADD:
        result = Double.valueOf(s1) + Double.valueOf(s2);
        break;
      case MINUS:
        result = Double.valueOf(s1) - Double.valueOf(s2);
        break;
      case TIMES:
        result = Double.valueOf(s1) * Double.valueOf(s2);
        break;
      case DIVISION:
        result = Double.valueOf(s1) / Double.valueOf(s2);
        break;
      default:
        result = null;
    }
    return result;

  }

  public static void main(String[] args) {
    //String math = "9+(3-1)*3+10/2";
    String math = "12.8 + (2 - 3.55)*4+10/5.0";
    try {
      doCalc(doMatch(math));
    } catch (Exception e) {
      e.printStackTrace();
    }
  }

}
